Exhaust driven supercharger for automotive vehicles



May 16, 1950 s. M. UDALE EXHAUST DRIVEN SUPERCHARGER FOR AU'I'OIOTIVE VEHICLES Filed July 15, 1944 2 Sheets-Sheet 1 s. M. UDALE 2,508,311 sxnws'r DRIVEN SUPERCHARGER FOR AUTOMOTIVE VEHICLES 2 Sheets-Sheet 2 May16, 1950 Filed July 15, 1944 Patented May l6, 1950 UNITED j STATES EXHAUST DRIVEN SUPERCHARGER FOR AUTOMOTIVE VEHICLES Stanley M. Udale, Detroit, Mich., assignor to George M. Holley and Earl Holley Application July 15, 1944, Serial No. 545,101

8 Claims.

The object of this invention, which is a continuation in part of Serial Number 510,842, filed November 17, 1943, is to permit the operation of an exhaust driven supercharger in normal weather at normal engine speeds and to prevent excessive operation in hot weather at high engine speeds so as to prevent the blades of an exhaust driven turbine being destroyed :by excessive temperature and to protect the engine from excessive loads at high speeds. The object of this application and of Serial No. 510,842, now Patent No. 2,434,726, is to apply an exhaust driven supercharger to engines on automotive vehicles as distinguished from airplanes.

Fig. 1 shows the preferred form of my invention.

Fig. 2 shows a partial cross-sectional elevation on plane 2-2 of Fig. 1.

Another object is to operate the turbine most effectively at the lower engine speed and less effectively at the higher engine speed (over 1200 revolutions per minute) so as to give the greater torque at the lower engine speed where the need for a supercharger is greater and where the danger of burning the blades is less compared with the danger at the higher engine speeds. Engines generally are more reliable at low engine speeds than at the higher speeds.

The figures show the preferred form of my invention.

In Figure 1, I is the air entrance, H is the exhaust driven supercharger which supplies air under pressure to the silencer l2, from which the air flows by a choke valve l3 and through a venturi M. The air flow is controlled by a throttle valve IS. The air then flows through an inlet manifold It in the middle of which is the hot spot l'l, controlled by the eccentrically mounted, thermostatically controlled valve I8. When the engine is first started and is cold then the exhaust gases flow out of exhaust outlet 20 and flow over valve l8, across the hot spot and down the passage 83 into the passage 22 or into the passage 2| when either of the valves 24 or 5-5 are open. After the engine has run for some time the valve I8 is rotated counter-clockwise into the position shown in Fig. 1 which rotation is determined by a coil spring thermostat l9. Fig. 2 shows the valve I8 in its starting or cold position. Valve I8 is thus opened by exhaust pressure and closed by spring I9. Spring is is made of bimetallic material so that it weakens at high temperatures and the valve I8 is opened by relatively low pressures at high temperatures 5 and vice versa. The lower left-hand side of valve 88 is longer than the upper right. Hence, when closed, that is, when horizontal, the left-hand side overbalances the right, and the valve turns anti-clockwise into the position in which it is 1 shown in response to an increase in exhaust pressure, that is, in response to an increase in revolutions per minute, providing the temperature of the thermostat is is high enough. When cold, the thermostat l9 resists the turning movement on the valve Hi. When the valve I8 is horizontal, the exhaust is directed against the hot spot l1 in a well-known manner .22 is an exhaust outlet, 2| is another outlet forming a bypass to and in parallel with the outlet 22. 23 is an exhaust driven turbine driving the supercharger I I and operated by the exhaust gas flowing in passage 22. 24 is an exhaust valve controlled by the throttle l5. When throttle i5 is open, exhaust valve 24 is closed and vice versa.

25 is the vacuum economizer valve which admits fuel only when the throttle I5 is substantially wide open. The diaphragm 26 controls the flow of fuel through the passage 21; 28 is a compression spring supporting the diaphragm 26. The pressure in the float chamber 31 is maintained at the pressure in the outlet from the silencer l2 by means of a passage 44. An opening 90 in the inlet manifold l6 allows the pressure in the inlet manifold IE to act on the diaphragm 26 and thus open the valve 25 at high supercharger pressure.

The cooling of the engine is controlled by the fan 29 driven by the pulley and belt 30. diator 45 cools the water from the jacket Of the 0 is blown by the fan 29 against the thermostatic The raengine and the air drawn through the radiator the pressure exerted by the spring 50 keeps the valve 55 closed until the air flow through the venturi creates a drop in pressure which opens the valve 55. Chamber 5| below the diaphragm 49 is connected through the pipe 52 with the throat of a small venturi 53. The upper side of the diaphragm is subjected to the inlet manifold suction or pressure as the case may be. The rod 48 is connected to the rod 54, which controls a valve 55, which permits exhaust gases to flow to the outlet 2| without passing through the gas turbine 23, when the throttle i5 is wide open and the temperature high. The fuel pump shown in the upper left-hand corner comprises a diaphragm 32 operated by the engine driven cam 33. Fuel is obtained from a tank 34 through pipe 35 past check valve 38 and discharges fuel past the discharge valve 39 through a pipe 36. The fuel flows through the pipe 36 to the float chamber 31. Air pressure pipe 4| connects the air entrance 42 with a chamber 43 located above the diaphragm 32. Chamber 43 contains the compression spring 40 which operates the diaphragm 32. The cam 33 raises the diaphragm 32 and the compression spring 40 depresses it pushing the fuel into the float chamber 31.

In order to prevent knocking at high engine .speed, water is admitted from a second float chamber 56 supplied with water through passage 51. A valve 58 controlled by the spring 59 shuts oil the flow of water when not needed.

The diaphragm 60 forms the lower wall of the chamber 6|, which is also connected to the pipe 4| so that the valve 58 is only open when the pressure in the pipe 4| exceeds atmospheric pressure. The water float chamber 56 is vented to the atmosphere through an opening 62.

In order to provide extra fuel for the extra air admitted during the operation of the supercharger, the valve 63 is provided, controlled by the diaphragm 64, which is moved by the thermostatic spring 65 acting in opposition to the compression spring 66. An increase in temperature causes valve 63 to rise. When the pressure rises in the float chamber 31, the diaphragm 64 rises and fuel is admitted to the chamber 61. Fuel admitted to the chamber 51 is discharged through the opening 63 in the throat of the venturi i4. Thermostat 65 is arranged so that when the temperature of the circumambient air generally referred to as "under the hood temperature" rises, the spring 65 weakens and permits the valve 63 to open more than it otherwise would, the reasonbeing that in hot weather the tendency, for the engine to burn its exhaust valve is less with a rich mixture than with a lean mixture.

The valve 55 is eccentrically mounted so that the back pressure created by the exhaust flowing through the turbine 23 has a tendency to open the valve 55, which is sufllciently large so that a comparatively small opening will allow a considerable quantity of exhaust gases to escape. The

turbine 23 and the guides therefor direct the exhaust so as to be most efiective at comparatively low engine speeds (1100 R. P. M.)

The lower part of radiator 45 is numbered 11 and is connected through the pipe 19 to the engine. The pipe 19 is the return passage for the water cooled in the radiator 45-11. 8| is the exit pipe for the hot water from the engine to the radiator 45-11.

Operation Assuming that the throttle I5 is wide open and the exhaust throttle 24 is closed, then at high speed above 2000 revolutions per minute,

there will be a tendency for the blades of the exhaust turbine 23 to burn out. However, the guide vanes i2 in the exhaust housing may be inclined at 30 so as to direct the flow of ex-, haust gases into the buckets in the turbine- 28, and the supercharger is thus most effective at the lower engine speeds, wide open throttle, e. g.. 1100 revolutions per minute. At higher engine speed, wide open throttle, the depression in the venturi 53 acts below the diaphragm 49, and the inlet manifold suction no longer acts above the diaphragm; hence, the thermostat 46 and spring 50 are the only elements holding the valve 66 closed. As the engine heats up, the thermostat 46 yields. The valve 55 being eccentrically mounted tends to open as the back pressure in the passage 22 builds up as the engine speeds up. The result is that when the engine is cold or in cold weather, the supercharger operates at its greatest power for a longer interval of time, but as the temperature increases, the element 46 collapses and becomes less eflective as a spring and the maximum power is developed for a shorter period.

The spring 50 is located in series with the thermostatic spring 46. The result will be that the valve 55 opens at a lower number of revolutions per minute at high temperatures than it opens at low temperatures, so that spring 50- and the thermostatic spring 46 jointly protect the exhaust turbine 23 under all conditions and they give more protection in hot weather than in cold weather. The thermostatic spring 46 being cooled by the fan 29 will not lose its temper. The supercharger is thus more effective in cold weather than in hot weather and more effective at lower speed. Because at high speed with the throttle wide open the depression'in venturi 53 is high relative to the pressure in the inlet manifold I6.

40 At such high speeds with the throttle wide open engines have a marked tendency to burn up,-as

far too much power is then developed. The only useful purpose a supercharger can possibly perform on a car or truck engine is to increase the torque at low and intermediate speeds. The valve 55 is eflective at higher speeds. At the higher speeds the supercharger is effective only at low temperatures; at lower speeds the supercharger is efiective at all temperatures.

The depression in the venturi 53 responds to the square of the revolutions per minute of the engine; hence, at the lower speeds it is relatively inefiective as compared with the exhaust pressure.

In order to stop the engine from knocking when the supercharger is in operation, it is desirable to add water and in some cases alcohol and water from the chamber 56 through the air passage 10. This water (or water and alcohol) is admitted into the air entrance i0 and so to the supercharger II from a small water carburetor. The diaphragm 60 is connected to the valve 56. which controls the discharge into the air entrance I. Valve 56 is held on its seat by spring 59 and is unseated by the supercharger pressure admitted to the chamber 5| onthe top of the diaphragm 60 through pipe 4|. Atmospheric pressure acts on the under side of the diaphragm 60.

increases appreciably above atmosphere especially in warm weather. The curved thermostatic spring I holds'the needle 63 in the closed position and admits the fuel to the orifice gradually as the supercharger pressure increases. The spring 85 weakens as the temperature increases to increase the supply of fuel. This additional fuel combined with the water added by the .water carburetor coupled with the thermostatically controlled bypass valve 55 cooperate to prevent the exhaust turbine 23 and the engine pistons and exhaust valves burning out on a hot day. The time intervalbefore the thermostat 46 would become hot enough to permit the valve 55 to open would depend on the sequence of events prior to the moment the valve it opened. These events would include the manner in which the vehicle had been operated, the temperature of the atmosphere, the load on the vehicle, the grade, the speed and the road resistance. The operator would soon discover that the supercharger quit working if he failed to use common sense.

The ordinary automotive engine at maximum speed is stressed to the safe limit and it is only at wide open throttle, low engine speed, that it is safe to subject the engine to the stresses involved in supercharging.

The time during which the water in the radiator 45 requires to become hot is the time during which the supercharger can safely be operated at relatively high speeds. Thetemperature of the air leaving the radiator 45 and impinging on the temperature responsive element 46, hence represents the result of all the events involved ,in the operation of the vehicle. The position of With ordinary automotive engines, a super-V charger is of most value at low engine speeds, as it is then that the engine stalls. More torque at low engine speed means less gear shifting. Fuel economy disappears once the engine is put into low gear and during the gear shift itself, stalling may occur if conditions are severe. I

Specifically, if 7 lbs. per square inch back pressure in theexhaust is created at 1100 revolutions per minute by the turbine 23, this will produce a superchargin of 7 lbs. per square inch in the supercharger ii if designed for this speed. At 2200 revolutions per minute, this should fall to zero; that is, the valve 55 should be open sufliciently as shown so that the supercharger is inoperative at 2200 revolutions per minute in cold weather, 2000 revolutions per minute in warm weather and 1700 revolutions per minute in hot weather.

What I claim is:

1. In an internal combustion engine having a radiator, a fan therefor and an exhaust driven turbo supercharger, means for preventing the overheating of the exhaust turbine comprising a water chamber connected to the air entrance, a water outlet, a valve therein, a moving wall responsive tothe supercharger pressure and connected to said valve, a spring adapted to close the valve and to engage with the moving wall in opposition to the supercharger pressure, an exhaust outlet from the engine to said turbine, an exhaust bypass. an unbalanced valve in said bypass designed to open under exhaust pressure to divert exhaust gases from said turbine, yieldable means tending to seat said valve against the ex- 78 connected to said air entrance, an exhaust pas-.

to the supercharger pressure for admitting extra fuel when the supercharger pressure exceeds a predetermined value.

2. In an internal combustion engine having an air entrance. a throttle controlled carburetor therein and an exhaust driven turbo supercharger adapted to supply air to the engine under pressure, control means therefor comprising an exhaust outlet directed to said turbo supercharger, a second exhaust outlet acting as a bypass to first outlet, a throttle valve insaid second exhaust outlet, control means therefor'connected to said carburetor throttle so that when the carburetor throttle is open, the exhaust throttle is closed, an additional exhaust outlet located in parallel with first exhaust outlet also acting as a bypass to the first outlet and, a second exhaust throttle in said additional exhaust outlet, means responsive to the exhaust pressure for opening said second exhaust throttle valve, yieldable means for closing said second exhaust throttle valve, temperature responsive means located on the outside of said exhaust outlet adjacent said valve adapted to increase the closing efiect of said yieldable means at low temperature, additional means responsive to the rate of air fiow produced by the action of said supercharger for opening said second exhaust throttle at high air flows.

3. In a liquid cooled internal combustion engine having an air entrance, at throttle-controlled carburetor therein and an exhaust driven turbo supercharger, adapted to supply air to the engine under pressure, comprising an exhaust outlet directed to said turbo supercharger, a second exhaust outlet acting as a bypass to first outlet, a throttle valve in said second exhaust outlet, control means therefor connected to said carburetor throttle so that when the carburetor throttle is open, the exhaust throttle is closed, an additional bypass exhaust outlet located in parallel to the first exhaust outlet, an exhaust throttle valve in said additional exhaust outlet, automatic means for closing said second exhaust throttle valve including a cooling radiator for said engine, a fan associated therewith, a temperatur responsive element located in the air stream from said radiator and connected to said exhaust throttle valve in said additional exhaust outlet so as to control the degree of opening of said exhaust throttle valve in said additional exhaust outlet.

4. In an internal combustion engine having an air entrance and a throttle valve therein, an exhaust driven turbine designed to be eflicient at low speeds, a supercharger driven thereby connected to said air entrance, an exhaust passage leading from the engine to said turbine, an exhaust bypass, a valve in said bypass adapted when open to divert the fiow of exhaust from said turbine so as to reduce the speed of said supercharger, means responsive to the speed 01 the air passing to the engine when the engine is operating with wide open throttle to open said exhaust valve so as to reduce the speed of said supercharger so that it is practicallyineifective at speeds above 2500 revolutions per minute.

5. In an internal combustion engine having an air entrance, a venturi therein, an exhaust 'driven turbine and a supercharger driven thereby and amp exhaust bypass, a valve in said bypass adapted when open to divert the flow of exhaust from said tunbine so as to reduce the speed of said supercharger, means responsive to the depression in the throat of said venturi to open said valve to protect the engine from the eflect of supercharging at high engine speed.

6. In a device as set forth in claim 5, in which there are temperature responsive means responsive to the temperature of the exhaust, said temperature responsive means being connected to the means responsive to the depression in the venturisoastopermitthe openingottheexhaust valve at a. lower engine speed at higher temperatures. STANIIY M. UDALE.

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